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import cv2
import numpy as np
import scipy.sparse
def mask_from_points(size, points):
""" Create a mask of supplied size from supplied points
:param size: tuple of output mask size
:param points: array of [x, y] points
:returns: mask of values 0 and 255 where
255 indicates the convex hull containing the points
"""
radius = 10 # kernel size
kernel = np.ones((radius, radius), np.uint8)
mask = np.zeros(size, np.uint8)
cv2.fillConvexPoly(mask, cv2.convexHull(points), 255)
mask = cv2.erode(mask, kernel)
return mask
def overlay_image(foreground_image, mask, background_image):
""" Overlay foreground image onto the background given a mask
:param foreground_image: foreground image points
:param mask: [0-255] values in mask
:param background_image: background image points
:returns: image with foreground where mask > 0 overlaid on background image
"""
foreground_pixels = mask > 0
background_image[..., :3][foreground_pixels] = foreground_image[..., :3][foreground_pixels]
return background_image
def apply_mask(img, mask):
""" Apply mask to supplied image
:param img: max 3 channel image
:param mask: [0-255] values in mask
:returns: new image with mask applied
"""
masked_img = np.copy(img)
num_channels = 3
for c in range(num_channels):
masked_img[..., c] = img[..., c] * (mask / 255)
return masked_img
def weighted_average(img1, img2, percent=0.5):
if percent <= 0:
return img2
elif percent >= 1:
return img1
else:
return cv2.addWeighted(img1, percent, img2, 1-percent, 0)
def alpha_feathering(src_img, dest_img, img_mask, blur_radius=15):
mask = cv2.blur(img_mask, (blur_radius, blur_radius))
mask = mask / 255.0
result_img = np.empty(src_img.shape, np.uint8)
for i in range(3):
result_img[..., i] = src_img[..., i] * mask + dest_img[..., i] * (1-mask)
return result_img
def poisson_blend(img_source, dest_img, img_mask, offset=(0, 0)):
# http://opencv.jp/opencv2-x-samples/poisson-blending
img_target = np.copy(dest_img)
import pyamg
# compute regions to be blended
region_source = (
max(-offset[0], 0),
max(-offset[1], 0),
min(img_target.shape[0] - offset[0], img_source.shape[0]),
min(img_target.shape[1] - offset[1], img_source.shape[1]))
region_target = (
max(offset[0], 0),
max(offset[1], 0),
min(img_target.shape[0], img_source.shape[0] + offset[0]),
min(img_target.shape[1], img_source.shape[1] + offset[1]))
region_size = (region_source[2] - region_source[0],
region_source[3] - region_source[1])
# clip and normalize mask image
img_mask = img_mask[region_source[0]:region_source[2],
region_source[1]:region_source[3]]
# create coefficient matrix
coff_mat = scipy.sparse.identity(np.prod(region_size), format='lil')
for y in range(region_size[0]):
for x in range(region_size[1]):
if img_mask[y, x]:
index = x + y * region_size[1]
coff_mat[index, index] = 4
if index + 1 < np.prod(region_size):
coff_mat[index, index + 1] = -1
if index - 1 >= 0:
coff_mat[index, index - 1] = -1
if index + region_size[1] < np.prod(region_size):
coff_mat[index, index + region_size[1]] = -1
if index - region_size[1] >= 0:
coff_mat[index, index - region_size[1]] = -1
coff_mat = coff_mat.tocsr()
# create poisson matrix for b
poisson_mat = pyamg.gallery.poisson(img_mask.shape)
# for each layer (ex. RGB)
for num_layer in range(img_target.shape[2]):
# get subimages
t = img_target[region_target[0]:region_target[2],
region_target[1]:region_target[3], num_layer]
s = img_source[region_source[0]:region_source[2],
region_source[1]:region_source[3], num_layer]
t = t.flatten()
s = s.flatten()
# create b
b = poisson_mat * s
for y in range(region_size[0]):
for x in range(region_size[1]):
if not img_mask[y, x]:
index = x + y * region_size[1]
b[index] = t[index]
# solve Ax = b
x = pyamg.solve(coff_mat, b, verb=False, tol=1e-10)
# assign x to target image
x = np.reshape(x, region_size)
x[x > 255] = 255
x[x < 0] = 0
x = np.array(x, img_target.dtype)
img_target[region_target[0]:region_target[2],
region_target[1]:region_target[3], num_layer] = x
return img_target